1. Field of the Invention
The present invention relates to a cosmetic that contains crosslinking organopolysiloxane having a hydrophilic functional group.
2. Description of the Related Art
Silicone oil has conventionally been used as a base oil in each composition in various fields such as cosmetic production due to its safe and reliable properties. Particularly in skin care and make-up cosmetics, a silicone oil having a low degree of viscosity of 100 mm2/s or less is widely used due to its properties such as excellent spreading properties, light feeling and reliable safety.
However, when, for example, a less fluid composition in the form of a paste is prepared from a low viscous silicone oil using as a base oil, it is necessary to use organic materials such as dextrin fatty acid ester (Patent Documents 1 to 4), sucrose fatty acid ester (Patent Document 5), trimethyl-silylated polyvinyl alcohol and trimethyl-silylated polysaccharide (Patent Document 6) and fatty acid ester group-containing cellulose ether (Patent Document 7), and organic modified clay minerals (Patent Documents 8 to 10) as a thickner. Nevertheless, conventional techniques fail to achieve a smooth and uniform composition in a cosmetic and maintain storage stability so as not to cause separation or discharge of a low viscous silicone oil.
To solve the problem, a method for obtaining a uniform composition in the form of a paste by using specific organopolysiloxane as a thickner and treating it with a low viscous silicone oil by shear force, was proposed (Patent Document 11). In addition, a composition obtained by introducing a long chain alkyl moiety to a molecule of a crosslinking organopolysiloxane used as a thickner to provide the same characteristics for a hydrocarbon oil and an ester oil was proposed (Patent Document 12).
Meanwhile, skin care and make-up cosmetics mostly include an emulsified composition blended with required components of not only an oil content but also moisture, and emulsified compositions are classified into oil-in-water, water-in-oil and multilayer emulsified compositions according to the type of blending. A composition using the above crosslinking organopolysiloxane as a thickner was certainly excellent in the effect of stably dispersing oil materials such as a silicone oil, a hydrocarbon oil and an ester oil, but failed to provide an emulsified composition in which water was also dispersed.
To solve the technical problem, a composition in which a polyoxyalkylene moiety is introduced in a molecule of crosslinking organopolysiloxane was proposed to obtain a stable water-in-oil emulsified composition (Patent Documents 13 and 14). Also, a composition that can solve the problem of odor found over time (Patent Document 15) and a composition in which polyglycerin moiety is introduced as a hydrophilic group (Patent Document 16) were proposed. In addition, a crosslinking organopolysiloxane capable of obtaining a favorable emulsified composition, even using a silicone oil and an organic oil such as a hydrocarbon oil and an ester oil as an oil material at the same time, was developed (Patent Document 17).
Such a crosslinking organopolysiloxane having a hydrophilic group in its molecule provides both a swelling property for an oil material and a water emulsifying property. Although the particle diameter for water dispersion is 10 to 20 μm, which is normally difficult to maintain storage stability, a water-in-oil emulsified composition excellent in storage stability can be obtained from the crosslinking organopolysiloxane (Non-Patent Document 1), and cosmetic compositions using this characteristic were proposed (Patent Documents 13, and 18 to 24).
Another characteristic in the crosslinking organopolysiloxane is to obtain a water-in-oil emulsified composition having a high inner water phase ratio (Patent Documents 25 to 27). In order to obtain a water-in-oil emulsified composition having a further improved thixotropy property of an oil phase, a cosmetic composition using both crosslinking organopolysiloxane having a hydrophilic group and crosslinking organopolysiloxane having no hydrophilic group was also proposed (Patent Documents 28 and 29).